Definition
A non-precision instrument approach procedure that uses WAAS (Wide Area Augmentation System) to provide lateral course guidance with localizer-like accuracy, but does not provide vertical guidance. The pilot flies the lateral track to a published Minimum Descent Altitude (MDA) and may only descend below that altitude when the required visual references are in sight. LP approaches are published at airports where terrain or obstacles prevent the publication of an LPV (Localizer Performance with Vertical Guidance) approach.
Plain English
An approach that uses GPS with WAAS to give you a precise side-to-side path to the runway, but does not tell you when to descend. You fly the centerline accurately, then level off at a set minimum altitude until you can see the runway.
Context Anchor
Seen on RNAV (GPS) instrument approach charts, usually in the minimums section as an LP line of minimums.
Derivation
"Localizer Performance" refers to the lateral accuracy being equivalent to that of an ILS localizer — the narrow, precise course that guides aircraft to a runway. "Without Vertical Guidance" simply means no glidepath is provided, so the approach behaves like a non-precision approach in the vertical sense.
Why Pilots Care
Tells the pilot the approach has higher minimums than those with vertical guidance and requires careful descent planning.
Grounding Statement
It gives strong left-right runway alignment guidance, but the pilot is still responsible for managing the descent by altitude.
Intuition Check
Do not assume “localizer” means an ILS localizer is being used. Here, it means GPS guidance with localizer-like left-right accuracy, but no approved vertical guidance.
Example Sentence 1
Because the airport had terrain on the approach end, only an LP approach was published instead of an LPV.
Example Sentence 2
During the briefing the crew noted that Localizer Performance without Vertical Guidance offers no electronic glidepath to follow.